Currently, mammographically-detected breast arterial calcifications (BAC) are considered an incidental finding without clinical importance since they are not associated with increased risk of breast cancer. However, presence of BAC on mammography correlates with several (but not all) traditional cardiovascular disease (CVD) risk factors and with prevalent and incident CVD. Thus, BAC detected during routine mammography is a noteworthy finding that could be valuable in identifying asymptomatic women at increased future CVD risk that may be candidates for more aggressive management. In addition, there are notable differences in measures of subclinical atherosclerosis burden in women (i.e., coronary artery calcification) by race/ethnic background, and the same appears to be true for BAC, although data are very limited. Another noteworthy limitation of prior research on BAC is the reliance on absence vs. presence of BAC;no study to date has determined gradation of BAC. The 3 specific aims are: 1) To establish a multi- ethnic cohort (n=5,400) between the ages of 60 and 79 years with equal representation of white (n=1,350;25%), African-American (n=1,350;25%), Asian (n=1,350;25%) and Hispanic/Latina (n=1,350;25%) women. All participants will be recruited at the time of their regular screening mammography (over a 2 year period) at three Kaiser Permanente of Northern California medical centers and will be free of clinical CVD at baseline. A new, validated densitometry method will be used to estimate BAC mass (in milligrams) using digital mammograms;2) To document race/ethnic variation in BAC mass and to examine associations of BAC mass with sociodemographic background, family history of CVD, traditional and novel CVD risk factors, reproductive health factors, psychosocial factors, selected mineral metabolism factors, selected medication use (statins and nitrogen-containing bisphosphonates), breast size and sleep-related factors;and 3) To elucidate the role of BAC mass in the prediction of coronary heart disease (CHD), cerebrovascular disease, heart failure, peripheral vascular disease and total CVD and to determine whether adding BAC mass to predictionmodels based on traditional risk factors improves classification of risk for total CVD and its components. Accomplishing these aims will provide novel insights into the utility of BAC mass as a screening tool to assess CVD risk. PUBLIC HEALTH RELEVANCE: Mammography is a common, inexpensive and widely accepted screening test that is recommended to all women starting at age 40;the detection and quantification of breast arterial calcification (BAC) in mammograms has the potential to be a useful marker of increased cardiovascular risk. If arterial calcium is noted (and particularly large amounts) in a routine mammogram, it may suggest the existence of a number of CVD risk factors and possibly an increased risk of future CVD events and thus may be a useful screening tool for identifying women at low or moderate risk who may benefit from more aggressive therapeutic intervention.